Generally, vehicle doors typically have a frame portion by which to guide and support a movable vehicle door glass. The frame portion provides a housing having a substantially U-shaped cross section that houses a similarly shaped rubber glass run channel. The glass run channel provides a channel for slidably engaging the movable vehicle door glass and guiding the door glass as it is moved between a raised position and a lowered position. The glass run channel further provides a proper seal against the door glass.
It has been observed that an audible chatter may occur upon the movable vehicle door glass being moved between the raised position and the lowered position, especially when moisture is present. Various factors are thought to combine and enhance the creation of the audible chatter. One such factor is the variance in friction between the rubber glass run channel and the surface of the door glass as the door glass moves within the glass run channel. The friction variation may be caused by waves and flat spots in the surface of the door glass which create a suction against the rubber glass run channel, especially when moisture exists between the door glass and the glass run channel. The glass chatter is enhanced with an increase in the door glass to rubber glass run channel contact ratio.
Other variables may also enhance the glass chatter and noise created by the movable vehicle door glass slidably engaging the rubber glass run channel, such as an electrically powered door glass that provides constant speed by which the door glass is moved between the raised position and the lowered position. Also, the use of certain door glass regulator mechanisms, such as single arm regulators, provide less stability than other door glass regulator systems, such as cross arm regulators, and therefore are more prone to glass chatter and noise due to the increased freedom of the door glass to move.